How Do You Drink Coffee In Space? With A Zero-Gravity Coffee Cup, Of Course

Scientists are conducting experiments aboard the International Space Station (ISS) to better understand how coffee behaves in microgravity.

On Earth, liquid coffee depends on gravity for its brewing process. Hot water drips onto fresh grinds, which strips the oil from the beans to create the cup of joe you rely on for that early-morning pick-me-up. Without gravity, however, brewing a cup of coffee is challenging, but so is finding a way to actually drink the caffeinated beverage once it's brewed.

"The coffee would be very hard to control," said physics professor Mark Weislogel of Portland State University. "In fact, it probably wouldn't [come out of the cup]. You'd have to shake the cup toward your face and hope that some of the hot liquid breaks loose and floats toward your mouth."

Weislogel and colleagues have been granted three patents to try and resolve problems in space involving liquids like coffee. One of the patents includes a low-gravity coffee cup, which NASA astronaut Don Pettit helped invent.

The zero-G coffee cup features one side with a sharp interior corner. NASA said that in microgravity, capillary forces send fluid flowing along the channel right into the lips of the drinker.

"As you sip, more fluid keeps coming, and you can enjoy your coffee in a weightless environment - clear down to the last drop," says Pettit. "This may well be what future space colonists use when they want to have a celebration."

The coffee experiment is part of the researchers' Capillary Flow Experiment on-board the orbiting laboratory. This experiment doesn't just look at coffee, but also cryogenic fuels, thermal coolants, potable water and urine. Having a better understanding of how these liquids behave in space will allow engineers to better plan spacecraft systems that use fluids.

"Our intuition is all wrong," said Weislogel. "When it comes to guessing what fluids will do in new systems, we are often in the dark."

One of the devices in the team's experiment looks at "interior corners." This experiment uses the capillary effect to help guide all kinds of fluids through spacecraft. The phenomenon is easier to study in space because of the lack of gravity. It is this method that led Pettit and Weislogel to create the zero-G coffee cup.

The team's Capillary Flow Experiment has also led them to create a microgravity condensing heat exchanger and another device that separates and controls multiphase fluids. Eventually, NASA said the team's patents could lead to better working toilets, air conditioning, fuel tanks and recycling systems.